We have not yet performed testing on Maya 2015, therefore we cannot guarantee functionality or provide support for it at this time.
There are also known issues with the Student Editions of Maya (for 2013 and 2014 versions), which did recently get some fixes.
Please view this forum thread for additional information and a link to the latest script, which might be able to help you.
https://.unrealengine.com/showthread.php?2447-Animation-and-Rigging-Tools-FAQ-Known-Issues-and-Feature-Roadmap
Cheers